Does it say anything on the len itself? Mine is an 85 Aspy. but maybe the same. Says tail lights. Maybe a loose bulb in the socket at the tail lights. I would tap around ( with your hand) on the tail lights and lens. See if you can get it to flicker on dash. Key on. If not take the bulb and socket out....see if the bulb is loose. Or just a bad ground/bulb. Both sides all sockets.